Methods and systems for obtaining an electrocardiogram signal of a patient via a non-adhering, direct contact electrode apparatus

ABSTRACT

Various methods and systems are provided for a fabric cover including a plurality of integrated electrodes for measuring an electrocardiogram signal of a patient in direct contact with at least a subset of the plurality of integrate electrodes. As one example, a fabric cover for an infant incubator or warmer includes a plurality of electrodes spaced apart from one another within a measurement area of a surface of the fabric cover adapted to have direct contact with a patient, the plurality of electrodes including a topmost electrode extending across an entire width of the measurement area, a bottommost electrode extending across the entire width of the measurement area, and a set of electrodes arranged between the topmost electrode and bottommost electrode, in a direction perpendicular to the width, within the measurement area.

FIELD

Embodiments of the subject matter disclosed herein relate to anapparatus including a plurality of electrodes, the apparatus adapted tohave direct, but non-adhering, contact with and measure anelectrocardiogram signal of a patient.

BACKGROUND

An electrocardiogram (ECG) may provide a measurement of electric signalsof the heart. Standard methods for measuring electric potential (e.g.,bio-potentials) of a patient, and obtaining an ECG signal of thepatient, may include securing electrodes directly to the skin of apatient. For example, a plurality of electrodes may be adhered to thepatient's skin via an adhesive. An acquired ECG signal may be used todiagnose heart conditions of the patient, as well as determine a heartrate of the patient. The heart rate may be used for patient monitoringand diagnosis. When used in neonatal or infant care applications (oftendirectly following delivery of the neonate/infant), the ECG signaland/or heart rate may be needed during resuscitation and/or monitoringof the patient for additional interventions.

BRIEF DESCRIPTION

In one embodiment, a fabric cover for an infant incubator or warmerincludes: a plurality of electrodes spaced apart from one another withina measurement area of a surface of the fabric cover adapted to havedirect contact with a patient, the plurality of electrodes including atopmost electrode extending across an entire width of the measurementarea, a bottommost electrode extending across the entire width of themeasurement area, and a set of electrodes arranged between the topmostelectrode and bottommost electrode, in a direction perpendicular to thewidth, within the measurement area.

It should be understood that the brief description above is provided tointroduce in simplified form a selection of concepts that are furtherdescribed in the detailed description. It is not meant to identify keyor essential features of the claimed subject matter, the scope of whichis defined uniquely by the claims that follow the detailed description.Furthermore, the claimed subject matter is not limited toimplementations that solve any disadvantages noted above or in any partof this disclosure.

BRIEF DESCRIPTION OF THE DRAWINGS

The present invention will be better understood from reading thefollowing description of non-limiting embodiments, with reference to theattached drawings, wherein below:

FIG. 1 shows an example of a neonate or infant care environmentincluding a fabric cover with integrated sensors for direct contact witha patient.

FIG. 2 shows an example block diagram of a system for measuringbio-potentials of a patient including an apparatus having a sensor arrayand a signal processing circuit.

FIG. 3 shows an example of a dynamic switching circuit for controllingthe sensors of the sensor array of FIG. 2.

FIG. 4 shows a schematic of example positions of a patient on a fabriccover including a plurality of integrated sensors for measuringbio-potentials of the patient.

FIG. 5 shows a flow chart of a method for dynamically switching a drivenelectrode of a sensor array of an apparatus in direct contact with apatient and determining an electrocardiogram (ECG) signal and/or heartrate of the patient from signals acquired from a plurality ofmeasurement electrodes of the sensor array.

FIGS. 6-10 show example arrangements of electrodes for a fabric coveradapted to be placed in direct contact with a patient.

FIG. 11 shows a schematic view of a fabric cover configured tofacilitate skin-to-skin contact between a patient and a care providerwhile measuring bio-potentials of the patient.

DETAILED DESCRIPTION

The following description relates to various embodiments of an apparatus(e.g., fabric cover) including a plurality of electrodes for measuringan electrocardiogram signal of a patient in direct contact with at leasta subset of the plurality of electrodes. For monitoring and care of apatient, such as a neonate or infant, an electrocardiogram (ECG) and/orheart rate signal of the patient may be acquired and displayed to a user(e.g., medical professional). As introduced above, standard electrodesfor measuring an ECG signal of a patient may be adhered to the skin ofthe patient. However, such electrodes which are stuck to the patient'sskin may cause damage to the more delicate skin of neonates or infants.Further, it may take a while for a medical professional to attach allthe ECG leads (e.g., electrodes). However, the time to attach the ECGelectrodes is often critical for administering essential and life-savingcare to the neonate or infant. In one example, after birth, a neonate orinfant may be placed in neonate or infant care environment (which mayinclude a bassinet, warmer or incubator), on top of a platform ormattress. An apparatus, such as a fabric cover (which may be in the formof a blanket, bed sheet, or mattress cover in some embodiments) mayinclude a plurality of electrodes (also referred to herein as sensors)attached or integrated therein. The fabric cover including anarrangement of electrodes may then be positioned in direct contact withthe patient (e.g., placed on top of the mattress, with the patient lyingdirectly on the fabric cover). When the patient is placed on the fabriccover with electrodes embedded therein, for example, a signal processingcircuit, such as the signal processing circuit shown in FIGS. 2 and 3,of or in electronic communication with electrodes of the fabric covermay automatically and immediately start acquiring bio-potential signalsof the patient. Though the electrodes of the fabric cover may be indirect contact with the skin of the patient, they may not be physicallyadhered (e.g., stuck) to the patient. As a result, as shown in FIG. 4,the patient may be able to move around across a surface of theelectrodes and fabric cover, thereby changing which electrodes of thefabric cover are in direct contact with the skin of the patient. Theelectrodes may be arranged in an array and include a plurality ofmeasurement electrodes (adapted to measure bio-potentials of thepatient) and one or more dedicated, driven electrodes (adapted to outputa driven, common mode output signal adapted to reduce noise of themeasured bio-potential signals). The acquired bio-potential signals maythen be used to determine an ECG signal and/or heart rate of thepatient. As shown by the method of FIG. 5, which of the electrodes arebeing used as the driven electrode for data acquisition may bedynamically switched during operation, based on which electrodes aredetermined to be in direct contact with the patient. As a result, a moreaccurate ECG signal with reduced noise may be obtained (continuously, inone example), even while a patient moves around on top of or against thefabric cover. This system may have minimal, passive contact with thepatient, while still allowing for direct contact with the skin of thepatient. As a result, an impact to the infant/neonate may be reduced.

FIG. 1 shows an example of a neonate or infant care environmentincluding a fabric cover with incorporated (e.g., integrated in oneembodiment) sensors for direct contact with a patient. Specifically,FIG. 1 shows a neonatal or infant care environment 100. As shown in FIG.1, environment 100 may include a neonate/infant radiant warmer 102,which may be referred to as a baby warmer that may include a mattress104 for supporting a patient 108 (e.g., a neonate or infant). Inalternate embodiments, environment 100 may be an incubator. In alternateembodiments, environment 100 may be a bassinet. The incubator and/orwarmer and/or bassinet may be used in the neonatal intensive care unit(NICU) and/or right after labor and delivery of an infant.

An apparatus 110 having a sensor array is positioned between themattress 104 and the patient 108. As used herein, the sensor array andsensors may also be referred to as an electrode array and electrodes,respectively. In the example shown in FIG. 1, the apparatus 110 is afabric cover 106 that is positioned on/over the mattress 104 such that atop surface 112 of the fabric cover 106 is in direct contact with thepatient 108. The fabric cover 106 includes a plurality of electrodes(e.g., sensors) integrated therein for measuring bio-potentials of thepatient 108. As described further below, the plurality of electrodes maybe arranged on the top surface 112 such that they may have directcontact with the skin of the patient 108. In one example, the fabriccover 106 may be a type of mattress pad or bed sheet. In anotherexample, the fabric cover 106 may be a blanket.

As described further herein, the apparatus 110 may provideelectrocardiogram (ECG) monitoring of patients such as neonates orinfants. Apparatus 110 may consist of multiple sensors (e.g.,electrodes) defining an array of sensors integrated with a remainder ofthe apparatus 110 (e.g., integrated with or sewn into a fabric of thefabric cover 106). The apparatus 110 may be transportable and reusable(e.g., washable). Further, the apparatus 110 may be inserted under thepatient, such as a neonate or infant, and upon any surface, such as ablanket, mattress (as shown in FIG. 1), or mother's chest or abdomen (asshown in FIG. 11). For example, as shown in FIG. 11 and as describedfurther below, the apparatus 110 may be integrated into a kangaroocare/wearable, skin-to-skin application, such as a sling, halter, wrap,nursing top, and the like. As described further below, apparatus 110 mayinclude electronics for direct contact measurement of bio-potentials(e.g., heart rate), signal conditioning and processing, and/or wired orwireless communication with additional electronics, processors, orcontrol units. Apparatus 110 may be configured for rapid measurement ofECG signals, even in the case where there is movement of the patientacross the surface of the apparatus 110 (such that the patient changeswhich sensors/electrodes of the apparatus 110 are in direct contact withthe patient). For example, apparatus 110 may enable measurement of ECGsignals through motion artifacts associated with the patient's movementson the apparatus 110 (e.g., on the bed sheet or blanket).

FIG. 2 shows an example block diagram of a system 200 for measuringbio-potentials of a patient (e.g., neonate or infant) including anapparatus 110 having a sensor array 201 and a signal processing circuit212. The apparatus 110 may be a fabric cover (such as fabric cover 106shown in FIG. 1, which may be a bed sheet, mattress cover, and/orblanket, in some embodiments, or such as fabric cover 1110 of FIG. 11,which may be a halter, sling, wrap, or the like). Thus, apparatus 110may be or include a fabric base 203 with a plurality of individualsensors or electrodes (202, 204, 206, and 208) of the sensor array 201integrated (e.g., embedded, sewn, incorporated, or affixed in some way)therein. As shown in FIG. 2, sensor array 201 includes four individualsensors 202, 204, 206, and 208, all spaced apart from one another (e.g.,not touching or directly contacting one another) via a gap (e.g.,distance) 205. However, in alternate embodiments, sensor array 201 mayinclude more or less than four individual sensors (e.g., two, three,five, eight, ten, etc.). The individual sensors of sensor array 201 maybe arranged in a pattern. Examples of different patterns of sensors ofthe sensor array for apparatus 110 are shown in FIGS. 4 and 6-10. Forall patterns, the individual sensors may be spaced apart from oneanother so that an amount of fabric of the fabric base 203 electricallyinsulates adjacent sensors from one another. In this way, electricalsignals are not transferred between sensors.

In one embodiment, each of the sensors of sensor array 201 may be anelectrode adapted to measure bio-potentials of the patient in directcontact with a surface of the sensors. The sensors (e.g., sensors 202,204, 206, and 208) may also be referred to herein as ECG sensors sincethey are adapted to measure electrocardiogram (ECG) signals from thepatient and determine a heart rate of the patient based on the measuredsignals. Sensor array 201 may include a plurality of measurementelectrodes (e.g., which receive and measure ECG signals from thepatient) and one or more dedicated, driven electrodes (e.g., whichoutput a driven common mode output signal to the patient). In someexamples, each of the measurement electrodes may be switched to be adriven electrode (e.g., switched from receiving bio-potential signalsfrom the patient to delivering the common mode output signal to thepatient). However, all of the dedicated, driven electrodes may remaindriven electrodes and may not be switchable to measurement electrodes.In this way, the electrodes designated as dedicated, driven electrodesmay only be used to output the driven common mode output signal and maynot be used for measuring bio-potentials of the patient. As describedfurther below, at any one time, one or multiple sensors may be selectedto actively be the driven electrode and deliver the driven, common modeoutput signal. In one embodiment, first sensor 202, second sensor 204,and third sensor 206 may be measurement electrodes while fourth sensor208 is a dedicated, driven electrode. In another embodiment, firstsensor 202 and second sensor 204 may be measurement electrodes whilethird sensor 206 and fourth sensor 208 are dedicated, driven electrodes.In yet another embodiment, each of first sensor 202, second sensor 204,third sensor 206, and fourth sensor 208 may be measurement sensorsadapted to be individually switched to functioning as a drivenelectrode. In yet another embodiment, each of first sensor 202, secondsensor 204, third sensor 206, and fourth sensor 208 may be measurementsensors and where second sensor 204 and third sensor 206 are adapted tobe both switched to functioning as a driven electrode. In this way,different combinations of measurement and driven electrodes included insensor array 201 are possible.

Each individual sensor (202, 204, 206, and 208) is electrically coupledto an electronic connector 210 via a different electrical connection209. In one embodiment, the electrical connections 209 may be conductivethreads woven or imbedded within the fabric base 203. In this way,electrical signals may be passed back and forth between the individualsensors and the connector 210. For example, signals received bymeasurement electrodes from the patient may be transferred to theconnector 210 via corresponding electrical connections 209 and thedriven common mode output signal may be sent to the driven electrodefrom the connector 210 via corresponding electrical connection 209. Asingle connector 210 is shown in FIG. 2. However, in alternateembodiments, there may be multiple connectors (e.g., one for eachindividual sensor of sensor array 201).

The signal processing circuit 212 of system 200 is electrically coupledto the connector 210 (or connectors) via a wired or wireless connection211. In one embodiment, all or select parts of the signal processingcircuit 212 may be included within apparatus 110 and the processedsignals may be transferred via a wireless connection to additionalprocessing electronics or a remote data acquisition and/or displaydevice. In this embodiment, the connector(s) 210 may be omitted.

Alternatively or additionally, the apparatus 110 may include anintegrated electronic layer 213 electrically coupled to (and/or includedwithin) the connector 210 and adapted to perform measurements onelectrical signals received from the plurality of sensors. For example,the integrated electronic layer may include one or more components ofsignal processing circuit 212 and/or dynamic switching circuit 300 (asdescribed further below with reference to FIG. 3). In anotherembodiment, as shown in FIG. 2, all the components of the signalprocessing circuit 212 may be located separate (e.g., remote) from theapparatus 110 and thus the connector(s) 210 and wired or wirelessconnection 211 may transfer electrical signals (acquired measurementsand the driven signal) between the apparatus 110 and the signalprocessing circuit 212. In some embodiments, the connector 210 mayinclude a wireless pod including a transmitter/receiver for transferringwireless signals between the apparatus 110 and the signal processingcircuit 212. In another embodiment, apparatus 110 may include a separatewireless pod electrically coupled with the connector 210 or eachindividual sensor of sensor array 201. In still another embodiment, suchas when the sensors and/or connector 210 are wirelessly connected to thesignal processing circuit 212, the sensors may receive electrical powervia a battery 230 incorporated into the apparatus 110 (e.g.,incorporated into the fabric cover).

In one embodiment, signal processing circuit 212 may be processor based.In one embodiment, signal processing circuit 212 may include one or moreinput/output interface devices 214 for communication with, e.g., sensors202, 204, 206, and 208 of sensor array 201, and/or one or more externalprocessing circuits. One or more input/output interface devices 214 mayinclude associated analog to digital and or digital to analog circuitryfor facilitating bi-directional signal communication with sensor array201. Signal processing circuit 212 may also include one or more centralprocessing units (CPU) 216, one or more memory devices 218 (e.g. arandom access memory (RAM) and/or cache memory, which may be volatile),one or more storage devices (e.g., non-volatile storage devices) 220,and one or more output devices 222. One or more memory devices 218and/or one or more storage devices 220 may define a tangible computerreadable storage medium of signal processing circuit 212. Signalprocessing circuit 212 may also include a power supply 224 which may bea battery-based power supply to facilitate mobile operation of signalprocessing circuit 212. One or more output devices 222, in oneembodiment, may be provided, e.g., by one or more of a display with orwithout an associated touch screen and/or one or more audio outputdevices (e.g., a speaker). Devices 214, 216, 218, 220, 222, and 224, inone embodiment, are in communication via a system bus 226. Signalprocessing circuit 212 may output data via an output device 222 whichmay include a bus-connected output device, as shown in FIG. 2 and/or toan output device of apparatus 110 which is provided as an output devicein communication with signal processing circuit 212 via input/outputinterface device 214.

FIG. 3 shows an example of a dynamic switching circuit 300 forcontrolling the ECG sensors (e.g., sensors 202, 204, 206, and 208) ofthe apparatus 110. In one embodiment, the dynamic switching circuit 300may be part of the signal processing circuit 212, such as part of theCPU 216. In another embodiment, the dynamic switching circuit 300 may beincluded on/within the apparatus 110, such as part of and/orelectrically connected with connector 210 (e.g., via integratedelectronic layer 213).

Dynamic switching circuit 300 includes sensor array 201 which includes aplurality of ECG sensors (e.g., electrodes). As discussed above withreference to sensor array 201 and FIG. 2, at least one (and in someexamples, at least two) of the ECG sensors of sensor array 201 arededicated, driven electrodes which selectively output a driven commonmode output signal and a plurality of the ECG sensors are measurementelectrodes adapted to measure bio-potentials of the patient and outputthese signals for determining the ECG signal of the patient. Themeasurement electrodes may also be switched to selectively output thedriven common mode output signal. Further, as described below, more thanone of the switchable measurement electrodes may be selected at any onetime to output the driven common mode signal. However, the dynamicswitching circuit 300 may dynamically switch which one of the availableelectrodes outputs the driven common mode signal, based on which sensorshave direct contact with skin of the patient lying on the apparatus 110.

Looking at FIG. 3, dynamic switching circuit 300 includes ECG sensors ofsensor array 201 in two-way electronic communication with defibrillatorprotection circuitry 302. The defibrillator protection circuitry 302 mayinclude a plurality of resistors and/or additional circuitry elementsthat absorb repetitive defibrillation and other high-energy pulses (suchas electrostatic discharge) to protect more sensitive electroniccircuitry elements in the dynamic switching circuit 300 and/or apparatus110. The defibrillator protection circuitry 302 is electrically coupled,via two-way electronic communication, to one or more input filters 304.As one example, the one or more input filters 304 may include one ormore filters (e.g., band-pass filters, adaptive filters, or the like)that filter out noise (such as common motion/movement noise from thepatient moving over/across the ECG electrodes) in the signals measuredby the measurement electrodes (and which are used to determine the ECGsignal of the patient). If using one or more adaptive filters to filterout common motion noise, at least two input channels, each including atleast 2 contact points between the ECG sensors and the patient's skin,and one driving electrode may be required. For example, in this case, atleast two of the ECG sensors in sensor array 201 which are determined tobe in direct contact with the patient's skin (e.g., at least a thresholdportion of the sensor is in direct contact with the patient, asexplained further below) may be selected as measurement electrodes and adifferent (third) one of the ECG sensors in sensor array 201, which isalso determined to be in direct contact with the patient's skin, may beselected as the driving electrode. The adaptive filter may adjust thefrequency range of signals received from the patient and may be executedby CPU 216.

Filtered signals from the input filter(s) 304 are electricallytransferred to one or more ECG differential amplifiers 306 foramplifying the measured signals from the patient. The amplified signalsare then electrically transferred to an input switch matrix 308. In oneexample, the input switch matrix 308 may determine which of themeasurement electrodes of the ECG sensors have contact with thepatient's skin and select signals received from those contactingmeasurement electrodes to transfer to an analog-to-digital converter(ADC) 310 for further processing and determination of the patient's ECGsignal and/or heart rate. In this way, the input switch matrix 308 mayselectively switch which measurement electrodes are used for obtainingsignals used to determine the patient's ECG signal and/or heart rate.Determining which ECG sensors have contact with the patient's skin mayinclude receiving signals from each and every one of the ECG sensors,which may include a measurement of skin impedance of the skin of thepatient, and determining which of the ECG sensors has contact with thepatient's skin based on which of the skin impedance measurements meet athreshold level (thereby indicating the sensor providing that signal hasa threshold amount of contact with the patient's skin and therefore mayprovide a strong enough signal for measuring the ECG signal of thepatient). The signals from the ECG sensors determined to have contactwith the patient's skin, and thus which are measurement electrodes, aretransferred to ADC 310 for further processing and determination of thepatient's ECG signal and heart rate. The measurement electrodes may eachbe connected to the ADC 310, and the input switch matrix 308 maydetermine which measurement electrodes have contact with the patient andcan thus be used to provide the driven common mode signal back to thepatient.

The ADC 310 converts the analog signals, filtered and amplified, fromthe selected measurement electrodes (ECG sensors) to digital signals forfurther processing and output. For example, from ADC 310, the converteddigital signals may be processed via additional electronics of thesignal processing circuit 212 to determine an ECG signal of the patientand a corresponding heart rate of the patient. These determined ECGsignals and/or heart rate may then be output to the user via one or moreoutput devices (e.g., output devices 222 of FIG. 2). As one example, theoutput device may be an electronic display device.

Based on the determination of which ECG sensors have sufficient contactwith the patient's skin providing low electrical impedance, and thus aredeemed contacting sensors, the input switch matrix 308 may also selectwhich of the measurement electrodes of the ECG sensors should be used asthe driven electrode for delivering the driven common mode outputsignal. For example, the input switch matrix 308 may determine whichinput measurement electrodes will be used to feed amplifier 312. Atleast one input measurement electrode may be selected by the inputswitch matrix 308, for example. In another example, all of the inputmeasurement electrodes may be used to feed amplifier 312, or any subsetthereof.

The input switch matrix 308 then communicates the selected ECG sensorsto be the driven electrode signal source and deliver those signalsources to a driven common mode output amplifier 312 which may generatethe driven common mode output signal. The driven common mode outputsignal and the selection of the driven electrode is then communicatedelectronically to an output switch matrix 314. The output switch matrix314 functions to switch which ECG contact is delivering the drivencommon mode output signal to the patient and deliver the driven commonmode output signal to the selected ECG sensors. In this way, theselection of which measurement electrodes will be switched and used fordriven output is determined by the output switch matrix 314.

In this way, signals generated and measured using one or more directlycontacting ECG sensors of sensor array 201 may be digitally sampled andcombined to form an ECG signal of the patient and determine thatpatient's heart rate according to the ECG signal. As explained above,the selection of the contacting ECG sensors for determining the ECGsignal may include, at the input switch matrix 308, selecting signalsfrom at least two contacting ECG sensors (e.g., two contact points) formeasurement signals and selecting one contacting ECG sensor to be thedriven electrode. In another example, the input switch matrix 308 mayselect signals from more than two contacting ECG sensors (if more thantwo ECG sensors are determined to be contacting the patient) formeasurement signals for determining the ECG signal and heart rate of thepatient.

Turning now to FIG. 4, a schematic is shown of example positions of apatient 424 on a fabric cover 410. Fabric cover 410 may be similar toapparatus 110 and/or fabric cover 106 discussed above with reference toFIGS. 1-3. As discussed above, the fabric cover 410 includes a pluralityof integrated ECG sensors 412, 414, 416, 418, 420, and 422 which may bereferred to herein as electrodes or electrode pads. Each of the ECGsensors are spaced apart from one another such that they areelectrically insulated from one another (and thus cannot pass signalsbetween one another, thereby reducing signal interference between ECGsensors) via the intervening fabric of the fabric cover 410. FIG. 4shows an example arrangement of ECG sensors on a surface of the fabriccover 410 which is not meant to be limiting and other arrangements ofECG sensors are possible. As shown in the example of FIG. 4, the ECGsensors include a topmost ECG sensor 412, a top-left ECG sensor 414, abottom-left ECG sensor 416, a bottommost ECG sensor 418, a bottom-rightECG sensor 422, and a top-right ECG sensor 420. The patient 424 may besmaller than the fabric cover 410 and thus may move around on top of andacross the surface of the fabric cover 410. As such, at different pointsin time, the skin of the patient may be in contact with different ECGsensors of fabric cover 410. Thus, the dynamic switching circuit of thesignal processing circuit included in or electrically coupled with thefabric cover 410 (such as dynamic switching circuit 300 of FIG. 3) mayswitch, in real-time (e.g., dynamically), which ECG sensors are selectedas the measurement electrodes and driven electrode for producing thepatient's ECG signal and determining the patient's heart rate, based onthe patient's position on the fabric cover 410 (as determined accordingto the methods described herein with reference to FIG. 3 and FIG. 5).

Specifically, FIG. 4 shows a first view 400 of the patient (e.g.,neonate or infant) 424 in a first position on the fabric cover 410(e.g., top-left corner). In this first position, the patient 424 is incontact with the topmost ECG sensor 412, the top-left ECG sensor 414,and the bottom-left ECG sensor 416. While a small portion of thepatient's arm may be contacting top-right sensor 420, there may not beenough skin-to-electrode contact to produce a strong enough skinimpedance and measurement signal. Thus, the dynamic switching circuit ofthe fabric cover 410 may select ECG sensors 412, 414, and 416 as thecontacting sensors (e.g., the ECG sensors having direct, face-sharingcontact with a portion of the skin of the patient 424). One of thecontacting ECG sensors 412, 414, and 416 may be selected to be thedriven electrode (sensor) while the remaining two are selected as themeasurement electrodes. Signals from the remaining ECG sensors (418,420, 422), which are determined to be non-contacting ECG sensors, may bediscarded (or not acquired) and not used to determine the ECG signal andheart rate of the patient. In one embodiment, ECG sensors 416 and 422may be dedicated, driven electrodes. Thus, the dynamic switching circuitmay automatically select bottom-left ECG sensor 416 to deliver thedriven common mode output signal. In alternate embodiments, a differentone or more of the ECG sensors of fabric cover 410 may be dedicated,driven electrodes. In yet another embodiment, all of the ECG sensors offabric cover 410 may be measurement electrodes (e.g., none are dedicatedto being driven only) adapted to switch between being measurement anddriven electrodes (as determined and selected by the dynamic switchingcircuit). However, by including some dedicated driven electrodes andsome switchable measurement electrodes, an electrode surface area isprovided that is always available for common mode noise reduction if allof the measurement electrodes can be used to capture the ECG signal(e.g., because the measurement electrodes have good patient contact),which may improve signal processing outcomes to mitigate motion andnoise artifacts using adaptive filtering by the CPU. Further, more ECGchannels may improve the adaptive filtering outcomes, while using themeasurement electrodes for providing the driven output reduces thenumber of channels available for signal processing post digitization,and thus it may be desirable to provide the dedicated, driven electrodesso that all possible channels may be available for the ECG signalacquisition.

FIG. 4 also shows a second view 402 of the patient 424 in a secondposition on the fabric cover 410 (e.g., top-right corner). In oneexample, the patient 424 may have moved from the first position (infirst view 400) to the second position (in second view 402), therebychanging which of the ECG sensors the patient 424 is in direct, physicalcontact with (and thus changing the contact points of fabric cover 410).In this second position, the patient 424 is in contact with the topmostECG sensor 412, top-right ECG sensor 420, and bottom-right ECG sensor422. Thus, patient 424 is no longer contacting ECG sensors 414 and 416and is newly contacting ECG sensors 420 and 422. Thus, in one example,the dynamic switching circuit may switch the driven electrode to be thebottom-right ECG sensor 422 (from the bottom-left ECG sensor 416 infirst view 400), in response to the patient moving positions on thefabric cover 410 and changing which ECG sensors are contacting sensors.Further, the dynamic switching circuit may continue to use the topmostECG sensors 412 as one measurement electrode and switch to using thetop-right ECG sensor 420 (instead of the bottom-right ECG sensor 416, asused in first view 400) as a second measurement electrode.

In a third view 404 of FIG. 4, the patient 424 is in a third position onthe fabric cover 410 (e.g., central-bottom region). In one example, thepatient 424 may have moved from the second position (in second view 402)to the third position (in third view 404), thereby changing which of theECG sensors the patient 424 is in direct, physical contact with (andthus changing the contact points of fabric cover 410). In this thirdposition, the patient 424 is in contact with the top-left ECG sensor414, the bottom-left ECG sensor 416, the bottommost ECG sensor 418, thebottom-right ECG sensor 422, and the top-right ECG sensor 420. Thus,patient 424 is no longer contacting the topmost ECG sensor 412, remainsin contact with ECG sensors 420 and 422, and is newly contacting ECGsensors 414, 416, and 418 (as compared to second view 402). Thus, in oneexample, the dynamic switching circuit may maintain the driven electrodeas the bottom-right ECG sensor 422 and not switch the driven electrodeto a different ECG sensor. Further, the dynamic switching circuit maycontinue to use the top-right ECG sensor 420 as one measurementelectrode and switch to using the top-left ECG sensor 414 and bottommostECG sensor 418 as additional measurement electrodes. In the case wherethe bottom-left ECG sensor 416 is a dedicated, driven electrode, it maybe used to apply the driven common mode output signal, in addition tothe bottom-right ECG sensor 422 that is currently selected as the drivenelectrode.

In a fourth view 406 of FIG. 4, the patient 424 is in a fourth positionon the fabric cover 410 (e.g., bottom-left). In one example, the patient424 may have moved from the third position (in third view 404) to thefourth position (in fourth view 406), thereby changing which of the ECGsensors the patient 424 is in direct, physical contact with (and thuschanging the contact points of fabric cover 410). In this fourthposition, the patient 424 is in contact with the top-left ECG sensor414, the bottom-left ECG sensor 416, and the bottommost ECG sensor 418.Thus, patient 424 is no longer contacting the top-right ECG sensor 420and bottom-right ECG sensor 422 (e.g., even though a small portion ofpatient 424 is shown contacting sensor 422, not enough of the patient'sskin is in contact with sensor 422, so the measured skin impedance ofthis sensor is below the threshold level) and remains in contact withECG sensors 414, 416, and 418 (as compared to third view 404). Thus, inone example, the dynamic switching circuit may switch the drivenelectrode to be the bottom-left ECG sensor 416 (from the bottom-rightECG sensor 422). Further, the dynamic switching circuit may continue touse the top-left ECG sensor 414 and bottommost ECG sensor 418 asmeasurement electrodes.

In all of the views of FIG. 4, at least two contacting ECG sensors areselected as measurement electrodes and a different, one contacting ECGsensor is selected as the driven electrode. As such, the patient's ECGsignal may be obtained with reduced noise (e.g., reduced noise frommotion of the patient) from the acquired signals. As shown in theexample of FIG. 4, the ECG sensors used as measurement electrodes andthe driven electrode may be selected based on which sensors aredetermined to be directly contacting the skin of the patient anddynamically switched as the patient moves across the fabric cover, intodifferent contacting positions, at least under some conditions. Forexample, the dedicated driven electrodes are fixed per the connection tothe signal processing circuit 212 via wired or wireless connection 211.The dedicated driven electrodes are always enabled and driven. If usingthe impedance measurement it is sensed that the driven electrodes arenot in contact with the patient, the system may then select whichmeasurement electrodes are to be used for driving the output signal.Which sensors are selected and used as the driven electrode andmeasurement (e.g., input) electrodes may be switched at any time duringoperation of the fabric cover (e.g., while the patient is on and/or incontact with the fabric cover). For example, switching of measurementand driven electrodes may be performed prior to the initial acquisitionof the ECG signal (from the measurement electrodes). In anotherembodiment, switching of the measurement and driven electrodes may occurduring ECG acquisition (e.g., while measurement signals are beingacquired from the measurement electrodes), in response to determiningthe contacting ECG sensors have changed (e.g., the ECG sensors currentlybeing used for determining the ECG signal are no longer in contact withthe patient and need to be switched to other sensors that are in contactwith the patient).

As shown in FIG. 4, multiple contacts between the patient and ECG sensorpads are made instantaneously upon application of the patient (e.g.,infant/neonate) to a surface of the fabric cover. While the multiplecontacts are direct contact points between the skin of the patient andthe ECG sensor pads, none of the ECG sensor pads are stuck ormechanically adhered to the patient's skin (e.g., via an adhesive),thereby reducing damage and irritation to the infant/neonate's delicateskin. As also seen in the different views of FIG. 4, the patient is freeto move over the surface of the fabric cover and sensor array. As such,the position of the patient on the sensor array may change, and thuswhich electrodes are in contact with the patient's skin may also changeduring operation/data collection. As discussed above and further below,the measurement and driven electrodes of the sensory array may beselected and switched according to this movement and change in thecontacting sensors.

FIG. 5 shows a flow chart of a method 500 for dynamically switching adriven electrode of a sensor array of an apparatus in direct contactwith a patient and determining an ECG signal and/or heart rate of thepatient from signals acquired from a plurality of measurement electrodesof the sensor array. In one example, the apparatus may be apparatus 110shown in FIGS. 1 and 2 and/or may be a fabric cover such as one or moreof fabric covers disclosed herein with reference to FIGS. 1, 4, and6-11. For example, the fabric cover may include one or more aspects ofthe fabric covers shown in FIGS. 1, 4, and 6-11. As disclosed herein,the apparatus or fabric cover may include a sensor array with aplurality of sensors (e.g., electrodes) spaced apart from one anotheracross a surface of the fabric cover. The fabric cover, and the sensorarray, is adapted to be in direct contact with a skin of a patient(e.g., a neonate or infant may be placed directly on top of the sensorarray of the fabric cover). However, the patient may freely move acrossthe surface of the fabric cover, thereby changing their position on thecover. As a result, not all sensors of the sensor array may becontacting (via direct contact) the patient at any one time, and whichsensors are in contact with the patient may change as the patientmoves/changes positions on the cover. As used herein, a “contactingsensor” of the sensor array may be defined as a sensor that isdetermined to be in direct contact with the skin of the patient and isthereby able to acquire a signal (e.g., bio-potential) from the patient.Additionally, as used herein, “direct contact” refers the electrodecontacting the skin of the patient without an intervening componentsarranged therebetween. In this way, the electrode and the skin of thepatient may have face-sharing contact.

Method 500 begins at 502 by, upon placement of a patient (e.g., infantor neonate) in contact with the sensor array of the fabric cover,receiving signals from the plurality of sensors (e.g., electrodes) ofthe sensor array. As an example, the method at 502 may include receiving(or acquiring) a signal from each sensor included in the sensor array.The received signals may be measurable bio-potentials of the patient andmay be of varying strengths (e.g., magnitudes). In some embodiments, ifone or more of the sensors are not in direct contact with the patient(e.g., not contacting the patient at all), the received signal maybe bezero, or below a lower threshold level, or measured impedance may behigher than a threshold level. As soon as the patient is placed incontact with the sensor array, signals from the sensors may beautomatically and instantaneously acquired by a signal processingcircuit of or in electrical communication with the fabric cover.

At 504, the method includes determining which sensors of the sensorarray are in direct contact with the patient based on individual skinimpedance measurements. For example, the signals received from thesensors at 502 may be used to determine an individual skin impedancemeasurement corresponding to each sensor. The method at 504 thenincludes determining, for each sensor of the sensor array, that theindividual sensor is in direct contact with the patient (and thus is acontacting sensor) in response to the individual skin impedancemeasurement of that sensor being above a threshold level. In oneexample, the threshold level may be a non-zero impedance valueindicating that the sensor (which may be a sensor pad, as discussedherein) has a large enough portion of its entire surface area in contactwith the skin of the patient in order to obtain a measurablebio-potential signal for determining the ECG signal (and heart rate) ofthe patient. If the individual skin impedance measurement of a sensor isnot below a threshold level, the method at 504 may include determiningthat the sensor is not in contact with the patient (and thus any signalreceived from that contact should not be used to determine the ECGsignal of the patient).

At 506, the method includes selecting a sensor, out of all the sensorsof the sensor array, to be used as a driven electrode based on whichsensors are determined to be contacting sensors (e.g., in contact withthe patient, as determined at 504) and outputting a driven common modeoutput signal via the selected sensor. As one example, the driven commonmode output signal may be a voltage of a magnitude that is appliedcontinuously via the selected driven sensor to the patient in order tocancel out electromagnetic interference due to patient movement/motionand other environmental artifacts such as power line frequencies etc..As explained above, in one embodiment, all sensors of the sensor arraymay be measurement sensors adapted to receive and measure bio-potentialsignals from the patient for processing into the ECG signal of thepatient. Each of these measurement sensors may be individuallyswitchable to functioning as the driven electrode by outputting thedriven common mode output signal. Any of these measurement sensors maybe selected as the driven electrode, if they are determined to be indirect contact with the patient at 504. In another embodiment, thesensor array may be split into a first set of sensors which aremeasurement sensors which may also be used as the driven electrode and asecond set of sensor which are dedicated, driven electrodes. Thededicated, driven electrodes may only be used to deliver the common modeoutput signal and may not be used to acquire signals from the patientfor determining the patient's ECG signal. In one example, the number ofdedicated, driven electrodes (sensors) may be less than the number ofmeasurement sensors. In this embodiment, the common mode output signalmay be delivered to driven electrode(s) for delivering the common modeoutput signal to the patient. If more than one dedicated, driven sensoris in contact with the patient, the sensor outputting the highest skinimpedance measurement may be selected to be the driven electrode.Alternatively, if more than one dedicated, driven sensor is in contactwith the patient, the processor may randomly select one of thecontacting, dedicated, driven sensors to be the driven electrode. In yetanother example, if more than one dedicated, driven sensor is in contactwith the patient, the processor may select a pre-determined (e.g.,stored in a memory of the signal processing circuit) to be the drivenelectrode and output the driven common mode output signal. In yetanother example, if more than one dedicated, driven sensor is in contactwith the patient, the processor may select all the dedicated drivenelectrodes and output the driven common mode output signal. If none ofthe dedicated, driven sensors are in direct contact with the patient,the processor may then select one of the measurement sensors that is indirect contact with the patient to be the driven electrode and switchthe selected measurement electrode from measuring bio-potentials of thepatient to outputting the driven common mode output signal. Examples ofselecting the sensor to be used as the driven electrode based onposition of the patient are shown in FIG. 4, as discussed above.

Method 500 then continues to 508 to receive (or continue receiving)signals from the contacting measurement sensors (e.g., measurementsensors in contact with the patient). In one example, only themeasurement sensors in direct contact with the patient may acquiresignals from the patient and transfer these to the signal processingcircuit. In another example, signals may be received by the signalprocessing circuit from every individual measurement sensor, even if thesensor is not in contact with the patient, and then only the receivedsignals from sensors with low contact impedance below a threshold may beused to determine the ECG signal, as described further below.

At 510, the method includes filtering the signals received from themeasurement sensors. As described above with reference to FIG. 3, thefilters may include one or more filters of varying types such asadaptive filters, band-pass filters, and the like. The method thencontinues to 512 to use the filtered signals from the measurementsensors determined to be contacting (e.g., in direct contact with) thepatient to determine the ECG signal for the patient and determine aheart rate of the patient from the determined ECG signal. For example,the dynamic switching circuit of the signal processing circuit may beadapted to select the filtered signals from only the measurement sensorsdetermined to be in direct contact with the patient (e.g., via an inputswitch matrix, such as the input switch matrix 308 shown in FIG. 3) andthen determine the patient's ECG signal from only these selectedfiltered signals. The patient's heart rate may then be determineddirectly from the determined ECG signal.

At 514, the method includes outputting the ECG signal and/or the heartrate to a user via an output device. In one example, the output devicemay be a display device in electronic communication with the signalprocessing circuit. The user may be a medical provider, such as atechnician, physician, or nurse. Method 500 may be run continuously suchthat the ECG signal and/or heart rate are continually determined andupdated and the display device may continuously display the updatedsignals, while signals are acquired from the patient via the sensorarray of the fabric cover. In this way, the user may monitor a conditionof the patient while the patient is in contact with the fabric cover,with minimal intervention (e.g., no adhesive electrodes are stuck to thepatient's skin).

Continuing to 516, the method includes determining whether thecontacting sensors have changed. For example, the method at 516 mayinclude determining whether the sensor previously (or most recently)selected as the driven electrode is no longer contacting the patient. Inthis case, the currently selected driven sensor may not be able todeliver the driven common mode output signal for noise reduction. If thecontacting sensors have not changed, the method continues to 518 tocontinue acquiring signals from the measurement sensors and using thesame (previously selected) sensor as the driven sensor. If any of thecontacting measurement sensors have changed, the method may furtherinclude continuing to acquire signals from the measurement sensors butswitching which measurement sensors signals are used to determine theECG signal (e.g., via selecting the signals from only the sensorsdirectly contacting the patient).

If the contacting sensors have changed, the method continues to 520 todynamically switch which sensor is used as the driven sensors (e.g.,electrode) while continuing to acquire signals from the contactingmeasurement sensors, if the currently-selected driven sensor is nolonger contacting the patient. For example, the method at 520 mayinclude switching from outputting the driven common mode output signalfrom a first sensor (determined to be no longer in direct contact withthe patient) to outputting the driven common mode output signal from asecond sensor (determined to be in direct contact with the patient). Anexample of such switching of which sensor is used as the drivenelectrode is shown in FIG. 4, as described above. Dynamically switchingwhich sensor is used as the driven electrode may include switching, inreal-time, as signals are continually acquired from the measurementsensors and as the patient moves across a surface of the sensor array(and changes position), which sensor outputs the driven common modeoutput signal. The switching at 520 may also include, if one or moremeasurement sensors are no longer contacting the patient, switchingwhich measurement sensors are used to determine the ECG signal.

FIGS. 6-10 show example arrangements of electrodes for a fabric cover,such as one of the fabric covers discussed herein. In particular, thefabric cover may be similar to the apparatus 110 and/or fabric covers106 and 410 described above with reference to FIGS. 1-4. Thus, thefabric covers discussed below with reference to FIGS. 6-10 may includesimilar components, including a sensor array including a plurality ofsensors integrated with a remainder of the fabric cover. In someembodiments, the fabric cover may be a bed sheet, mattress cover,blanket, or wearable article such as a sling or wrap. The plurality ofsensors may be in the form of electrode pads and may be adapted to bemeasurement and/or driven electrodes, as discussed herein. In oneembodiment, both the fabric base of the fabric cover and the electrodepads may be porous in order to interface with the skin and allow for theexchange of humidity and gases through them, while still enablingmeasurement from the electrode pads. The array of electrode pads on asurface of the fabric cover may be sized to include a selected number ofelectrode pads to accommodate a range of sizes of patients from neonatesto older babies to adults.

The fabric covers discussed below with reference to FIGS. 6-10 may beoptimized to maximize a separation distance (e.g., gap) betweenadjacently arranged electrodes (e.g., electrode pads), maximize a numberof the electrodes within the electrode array, maximize the electrodesseparation distance, and maximize a surface area of each electrode. Forexample, by having an increased number of potential contact points(where each electrode pad is considered a contact point) while at thesame time maximizing a surface are of each contact point, within a setarea for the electrode array (referred to as the measurement area, asexplained further below), an increased number of sensor signals fordetermining the ECG signal may be acquired, even as the patient changesposition on the fabric cover, thereby increasing an accuracy of the ECGsignal and reducing signal noise. Maximizing the separation distancebetween electrodes allows acquisition of a stronger signal peak-peakvoltage. The various embodiments discussed below with reference to FIGS.6-10 aim to achieve this arrangement of electrode pads.

Turning first to FIG. 6, a first embodiment of a fabric cover 600 isshown having a fabric base 602 with a plurality of electrode padsintegrated therein. The electrode pads include semi-circular electrodepads 604 arranged at topmost and bottommost positions of a measurementarea 608 of the fabric base 603 of fabric cover 600 while a plurality ofrectangular electrode pads 606 are arranged therebetween. In alternateembodiments, electrode pads 606 may have a different shape, such assquare, circular, semi-circular, oval, hexagonal, or the like.

The measurement area 608 is defined as the area of the fabric coverincluding all the electrode pads of the sensor array of the fabriccover. There may be no electrode pads (e.g., electrodes) arrangedoutside a perimeter of the measurement area 608. As shown in FIG. 6,both the semi-circular electrode pads 604 extend across an entire width610 of the measurement area 608 and each of the rectangular electrodepads extend across only a portion of the width 610. By having topmostand bottommost electrode pads that extend across an entire width of themeasurement area, it may be more likely to obtain a contact point ateither end of the patient. For example, both of the semi-circularelectrode pads 604 may be dedicated driven electrodes, and the extentand shape of the semi-circular electrode pads may optimize contact withthe patient's head if the patient is rolling or moving relative to thefabric cover.

Each electrode pad of the rectangular electrode pads 606 is arrangeddirectly adjacent to two other electrode pads of the rectangularelectrode pads 606 and one of the semi-circular electrode pads 604. Thespacing, arrangement, and/or shape of the rectangular electrode pads 606may optimize contact with the torso area of the patient for ECG signalacquisition. There is a gap 612 arranged between adjacently arrangedelectrode pads. The gap 612 may be of varying sizes. In one example, gap612 may be less than a threshold distance, such as half an inch.However, in alternate examples, gap 612 may be between 0.25 and 0.5inches or between 0.4 and 0.6 inches. The larger the gap between twosignal electrodes, the higher the skin impedance is between them, andtherefore the larger the amplitude of the measured ECG signal is. Thematerial within gaps 612, between the electrode pads, is the fabricmaterial of the fabric base 602 and may be insulating such thatelectrical signals are not transferred between adjacent electrode pads.

FIG. 7 shows a second embodiment of a fabric cover 700 having the fabricbase 602 with a plurality of electrode pads integrated therein. In thisembodiment, the electrode pads include semi-circular electrode pads 702arranged at topmost and bottommost positions of measurement area 608.Semi-circular electrode pads 702 have a smaller height (directionperpendicular to width 610) than the semi-circular electrode pads 604 ofFIG. 6. The electrode pads also include rectangular electrode pads 704which each extend across a majority of the entire width 610 ofmeasurement area 608. In alternate embodiment, each of or a portion ofelectrode pads 704 may extend across the entire width 610. Further, insome embodiments, rectangular electrode pads 704 may have an alternateshape such as oval, rectangular with semi-circular ends, semi-circular,or the like. As in FIG. 6, adjacent electrode pads are separated by gap612 which may vary between different pairs of electrode pads or may bethe same for each adjacent pair of electrode pads.

The fabric covers disclosed herein may be comprised of a fabricmaterial, including one or more of cotton, nylon, rayon, spandex, or thelike. The electrodes (electrode pads) and electrical connections betweenthe electrode pads and connectors or connecting elements, as well as theconnectors (or leads) may be comprised of a conductive depositedmaterial such as silver. For example, the electrode pads and electricalconnections and/or connectors may be silver deposited electrode layerson a fabric base comprising one or more of the fabric materials listedabove. A masking or etching process may be used to define the activeelectrode areas and their corresponding conductive electricalconnections (e.g., signal routes to the connectors). This is in contrastto the non-conductive or insulated areas of the fabric base of thefabric cover. Using silver material for the electrodes and/or signalpaths may allow for electrical signal transmission, while at the sametime providing antibacterial properties with increasedbio-compatibility. Signal routing paths (electrical connections) fromeach electrode pad to a connector or measurement point at an electronicinterface of the fabric cover may be insulated from undesired patientskin contact by the addition of a dielectric layer. The electricalcontacts or connectors (such as connector 210 shown in FIG. 2) measuringor receiving the signals from each electrode pad may be a simpleconnector with spring force contact pads on the fabric base withsufficient pitch density, thereby enabling the connection to passbio-potential signals to a data acquisition front end device (e.g.,which may be part of the signal processing unit), either via a wiredcable from the connector, or directly to an integrated electronic layerperforming measurements on the fabric cover and transmitting the data toa monitoring station wirelessly.

The fabric cover may be intended for single use or repeated use. Forexample, the fabric cover may be washable between uses (e.g., betweenpatients). However, the fabric cover may have a finite number of uses asthe electrical contacts and/or electrode pads may degrade over time dueto contact with water during washing.

Turning now to FIGS. 8-10, additional embodiments of arrangements ofelectrode pads of a fabric cover and electrical connections (e.g.,signal routes) from each electrode pad to a measurement point (which mayinclude a connector, in one example) are shown. In particular, FIG. 8shows a first fabric cover 800 with a similar arrangement of electrodepads to that of FIG. 7. For example, fabric cover 800 includes topmostand bottommost semi-circular electrode pads 802 and a plurality ofelongate electrode pads 804 arranged therebetween. Each electrode pad iscoupled to an individual measurement point 806 by an electricalconnection 808. Each measurement point 806 may be coupled to or includeits own connector (e.g., similar to connector 210 of FIG. 2) or allmeasurement points on a same side of the fabric cover may couple to acommon connector, the common connector in electronic communication withadditional signal processing electronics via a wired or wirelessconnection. All or a portion of the additional signal processingelectronics may be included on the fabric cover or off (e.g., remotefrom) the fabric cover.

FIG. 9 shows a second fabric cover 900 with a different arrangement ofelectrode pads including topmost and bottommost semi-circular electrodepads 902 and a plurality of hexagonal electrode pads 904 arrangedbetween. Some of the hexagonal electrode pads 904 may be partial (e.g.,cut in half) hexagons in order to accommodate a honey-comb likearrangement of the hexagonal electrode pads (e.g., adjacent hexagons areoffset in an alternating pattern), as shown in FIG. 9. Each of thehexagonal electrode pads 904 are spaced apart from one another and thesemi-circular electrode pads 904. In alternate embodiments, thehexagonal electrode pads 904 may have an alternate polygon shape, suchas pentagonal, heptagonal, octagonal, decagonal, and the like. Similarlyto as described above with reference to FIG. 8, each electrode pad ofFIG. 9 is coupled to an individual measurement point 906 by anelectrical connection 908.

FIG. 10 shows a third fabric cover 1000 with yet another arrangement ofelectrode pads including topmost and bottommost semi-circular electrodepads 1002, a plurality of elongate electrode pads 1006, and a pluralityof rectangular electrode pads 1004. Specifically, FIG. 10 shows two rowsof rectangular electrode pads 1004 separated from one another via twoelongate electrode pads 1006 (which are spaced apart from one anotherand an adjacently arranged row of rectangular electrode pads 1004), andan elongate electrode pad 1006 positioned between each row ofrectangular electrode pads 1004 and one of the semi-circular electrodepads 1002. However, in alternate embodiments, the third fabric cover1000 may include additional or fewer rows of rectangular electrode pads1004 and more or fewer elongate electrode pads 1006 spaced betweenadjacent rows of rectangular electrode pads 1004 and/or a row ofrectangular electrode pads 1004 and a semi-circular electrode pad 1002.Similarly to as described above with reference to FIG. 8, each electrodepad of FIG. 10 is coupled to an individual measurement point 1008 by anelectrical connection 1010.

FIG. 11 shows a schematic view 1100 of a patient 1124 positioned on acare provider 1102 and held in position with a fabric cover 1110. Fabriccover 1110 may be similar to apparatus 110 and/or fabric cover 106discussed above with reference to FIGS. 1-3. However, as shown in FIG.11, the fabric cover 1110 may be in the form of a wearable articleconfigured to facilitate skin-to-skin contact between the patient 1124and the care provider 1102 (which may be a parent of the patient orother care provider). Thus, the fabric cover 1110 may be in the form ofa wrap, a sling, a carrier, a nursing top, or other wearable article. Asshown, the patient 1124 is positioned between the care provider 1102 andthe fabric cover 1110, such that the patient 1124 is in direct,skin-to-skin contact with the care provider 1102 (e.g., via a first sideof the patient) and the patient 1124 is in direct, skin-to-fabric and/orelectrode contact with the fabric cover 1110 (e.g., via a second,opposite side of the patient).

As discussed above, the fabric cover 1110 includes a plurality ofintegrated ECG sensors 1112, 1114, 1116, 1118, 1120, and 1122 which maybe referred to herein as electrodes or electrode pads. Each of the ECGsensors are spaced apart from one another such that they areelectrically insulated from one another (and thus cannot pass signalsbetween one another, thereby reducing signal interference between ECGsensors) via the intervening fabric of the fabric cover 1110. FIG. 11shows an example arrangement of ECG sensors on the fabric cover 1110which is not meant to be limiting and other arrangements of ECG sensorsare possible. Further, the ECG sensors on the fabric cover 1110 may bepositioned on a patient-facing surface of the fabric cover 1110, suchthat the electrodes may make direct contact with the patient 1124, whilean insulating layer (not shown in FIG. 11 for visual purposes) may forman outer-facing surface of the fabric cover 1110.

As shown in the example of FIG. 11, the ECG sensors include a topmostECG sensor 1112, a top-left ECG sensor 1114, a bottom-left ECG sensor1116, a bottommost ECG sensor 1118, a bottom-right ECG sensor 1122, anda top-right ECG sensor 1120. The patient 1124 may be smaller than thefabric cover 1110 and thus may move around across the patient-facingsurface of the fabric cover 1110. As such, at different points in time,the skin of the patient may be in contact with different ECG sensors offabric cover 1110. Thus, the dynamic switching circuit of the signalprocessing circuit included in or electrically coupled with the fabriccover 1110 (such as dynamic switching circuit 300 of FIG. 3) may switch,in real-time (e.g., dynamically), which ECG sensors are selected as themeasurement electrodes and driven electrode for producing the patient'sECG signal and determining the patient's heart rate, based on thepatient's position on the fabric cover 1110 (as determined according tothe methods described herein with reference to FIG. 3 and FIG. 5).

The fabric cover 1110 may be similar to the fabric covers describedabove, and thus may be comprised of a fabric material, including one ormore of cotton, nylon, rayon, spandex, or the like. The electrodes maybe similar to the electrodes described above, and thus the electrodes(electrode pads) and electrical connections between the electrode padsand connectors or connecting elements, as well as the connectors (orleads) may be comprised of a conductive deposited material such assilver, e.g., silver deposited electrode layers on a fabric basecomprising one or more of the fabric materials listed above.

The fabric cover 1110 may be configured to maximize electrode contactwith the patient 1124 while minimizing electrode contact with the careprovider 1102. Thus, the electrodes integrated in the fabric cover 1110may be positioned on the fabric cover 1110 in a measurement region thatis positioned to preferentially contact the patient. The fabric covermay include straps, fasteners, or other features not shown in FIG. 11 tofacilitate secure positioning of the patient 1124 relative to the careprovider 1102 while also ensuring maximum contact between the patient1124 and the electrodes. The fabric cover 1110 may include an insulatinglayer on an outer-facing surface of the fabric cover 1110, opposite thepatient-facing surface and integrated electrodes, which may preventcontact between the care provider 1102 and the electrodes.

However, given the high likelihood for patient movement and small sizeof the patient relative to the care provider 1102, and further given thedesire to maximize patient contact with the electrodes even as thepatient moves (and hence wide/long extension of the electrodes acrossthe fabric cover), it may not be possible to prevent inadvertent contactbetween one or more of the electrodes and the care provider during allconditions, or otherwise insulate the care provider from contributinginterference to the ECG signal of the patient. Thus, at least in someexamples, before and/or during patient ECG signal acquisition, adiagnostic routine may be performed to determine if the care provider iscontributing to the ECG signal acquired by the system. If the careprovider is contributing to the ECG signal, the acquisition of the ECGsignal may be paused until the care provider is no longer contributingto the ECG signal, or the contribution to the ECG signal from the careprovider may be filtered out.

FIGS. 1 and 6-10 show example configurations with relative positioningof the various components. If shown directly contacting each other, ordirectly coupled, then such elements may be referred to as directlycontacting or directly coupled, respectively, at least in one example.Similarly, elements shown contiguous or adjacent to one another may becontiguous or adjacent to each other, respectively, at least in oneexample. As an example, components laying in face-sharing contact witheach other may be referred to as in face-sharing contact. As anotherexample, elements positioned apart from each other with only a spacethere-between and no other components may be referred to as such, in atleast one example. As yet another example, elements shown above/belowone another, at opposite sides to one another, or to the left/right ofone another may be referred to as such, relative to one another.Further, as shown in the figures, a topmost element or point of elementmay be referred to as a “top” of the component and a bottommost elementor point of the element may be referred to as a “bottom” of thecomponent, in at least one example. As used herein, top/bottom,upper/lower, above/below, may be relative to a vertical axis of thefigures and used to describe positioning of elements of the figuresrelative to one another. As such, elements shown above other elementsare positioned vertically above the other elements, in one example. Asyet another example, shapes of the elements depicted within the figuresmay be referred to as having those shapes (e.g., such as being circular,straight, planar, curved, rounded, chamfered, angled, or the like).Further, elements shown intersecting one another may be referred to asintersecting elements or intersecting one another, in at least oneexample. Further still, an element shown within another element or shownoutside of another element may be referred as such, in one example.

In this way, a fabric cover may include a plurality of electrodesarranged on a surface of the fabric cover in order to measure and ECGsignal and/or a heart rate of a patient. The surface of the fabric coveris adapted to have direct contact with the patient (e.g., the patientmay be placed on top of and/or against the fabric cover). However, theelectrodes may not be mechanically adhered (via adhesive or other means)to the patient and the patient may be allowed to feely move across thesurface of the fabric cover. As such, a signal processing circuit of thefabric cover may determine which electrodes of the plurality ofelectrodes have direct contact with the patient's skin and, duringsignal acquisition via the electrodes, dynamically switch whichelectrode of the plurality of electrodes is used to output a driven,common mode output signal and which electrode signals are used todetermine the patient's ECG signal. As a result, a more accurate ECGsignal and heart rate of the patient, with reduced noise, may beacquired and used for diagnosis and interventions, even as the patientmoves across and changes position on the fabric cover. The technicaleffect of, while a patient is in direct contact with a fabric surfacehaving a plurality of electrodes integrated therein, receiving signalsfrom the plurality of electrodes; selecting at least a first electrodeof the plurality of electrodes as a measurement electrode and a secondelectrode of the plurality of electrodes as a driven electrode based onthe received signals; receiving and processing signals from at least thefirst electrode to determine and output an electrocardiogram signal ofthe patient with reduced noise; and dynamically switching whichelectrode of the plurality of electrodes is selected as the drivenelectrode in response to a change in which electrodes of the pluralityof electrodes are in direct contact with the patient is to obtain, morequickly, a more accurate ECG signal and heart rate with reduced noise,while also reducing irritation to the patient's skin. As such, insituations where time to intervene or treat a patient is more critical(as for an infant or neonate following delivery), patient treatmentbased on ECG signal and/or heart rate may be delivered more quickly andeffectively.

As one embodiment, a fabric cover for an infant incubator or warmerincludes a plurality of electrodes spaced apart from one another withina measurement area of a surface of the fabric cover adapted to havedirect contact with a patient, the plurality of electrodes including atopmost electrode extending across an entire width of the measurementarea, a bottommost electrode extending across the entire width of themeasurement area, and a set of electrodes arranged between the topmostelectrode and bottommost electrode, in a direction perpendicular to thewidth, within the measurement area. In a first example of the fabriccover, each electrode of the set of electrodes extends across a majorityof the entire width of the measurement area. In a second example of thefabric cover, which optionally includes the first example, eachelectrode of the set of electrodes is arranged directly adjacent to twoother electrodes of the set of electrodes and one of the topmost andbottommost electrodes. In a third example of the fabric cover, whichoptionally includes one or both of the first and second examples, thetopmost electrode and the bottommost electrode are dedicated, drivenelectrodes and wherein each electrode of the set of electrodes is ameasurement electrode. In a fourth example of the fabric cover, whichoptionally includes one or more or each of the first through thirdexamples, each electrode of the plurality of electrodes and the fabriccover are porous. In a fifth example of the fabric cover, whichoptionally includes one or more or each of the first through fourthexamples, the fabric cover further includes at least one electricalconnector and a plurality of electrical leads, each electrical lead ofthe plurality of electrical leads being insulated from the plurality ofelectrodes via a dielectric layer and extending between a respectiveelectrode and the at least one electrical connector. In a sixth exampleof the fabric cover, which optionally includes one or more or each ofthe first through fifth examples, the at least one electrical connectoris wirelessly connected to a signal processing circuit via a wirelesselectrical connection. In a seventh example of the fabric cover, whichoptionally includes one or more or each of the first through sixthexamples, the fabric cover further includes an integrated electroniclayer electrically coupled to the at least one electrical connector andadapted to perform measurements on electrical signals received from theplurality of sensors. In an eighth example of the fabric cover, whichoptionally includes one or more or each of the first through seventhexamples, the integrated electronic layer includes a dynamic switchingcircuit including an input switch matrix and output switch matrixadapted to switch which electrode of the plurality of electrodes isdriven to output a driven common mode output signal and which signalsreceived from the plurality of electrodes are used to determine anelectrocardiogram signal of the patient. In a ninth example of thefabric cover, which optionally includes one or more or each of the firstthrough eighth examples, the plurality of electrodes receive electricalpower via a battery incorporated into the fabric cover. In a tenthexample of the fabric cover, which optionally includes one or more oreach of the first through ninth examples, each electrode of theplurality of electrodes is an electrode pad including silver depositedelectrode layers and wherein each electrode and a correspondingelectrical connection between the electrode and an electrical connectoror measurement electronics is conductive while a remainder of the fabriccover is non-conductive.

As another embodiment, a system for measuring bio-potentials of apatient includes a plurality of electrodes spaced apart from one anotheralong a surface adapted to be placed in direct contact with the patient;and an electronic processor in electronic communication with each of theplurality of electrodes and adapted to: obtain signals output from atleast two measurement electrodes of the plurality of electrodes that arein direct contact with the patient and dynamically switch whichelectrode of the plurality of electrodes is selected as a drivenelectrode while at least a portion of the surface is in contact with thepatient. In a first example of the system, the plurality of electrodesincludes a first set of dedicated, driven electrodes adapted to onlyoutput a driven common mode output signal and second set of measurementelectrodes adapted to measure bio-potentials of the patient, where thedriven electrode is selected from the first set of dedicated, drivenelectrodes and the two measurement electrodes are selected from thesecond set of measurement electrodes. In a second example of the system,which optionally includes the first example, the first set of dedicated,driven electrodes includes at least two electrodes, wherein there are agreater number of electrodes in the second set of measurement electrodesthan the first set of dedicated, driven electrodes, and wherein theplurality of electrodes are spaced apart from one another via a gap,that gap including material that insulates adjacent electrodes from oneanother. In a third example of the system, which optionally includes oneor both of the first and second examples, the electronic processor isfurther adapted to: determine which electrodes of the plurality ofelectrodes are in direct contact with the patient based on individualskin impedance measurements received from each electrode of theplurality of electrodes and select the driven electrode to be anelectrode having an individual skin impedance measurement at a thresholdlevel. In a fourth example of the system, which optionally includes oneor more or each of the first through third examples, the electronicprocessor is further adapted to determine an electrocardiogram signal ofthe patient from signals output by the at least two measurementelectrodes, the at least two measurement electrodes determined to be indirect contact with the patient, wherein the electrodes having signalsused for determining the electrocardiogram signal do not include theselected driven electrode. In a fifth example of the system, whichoptionally includes one or more or each of the first through fourthexamples, the electronic processor is further adapted to determine aheart rate of the patient from the determined electrocardiogram signaland display, via a display device, one or more of the determined heartrate and electrocardiogram signal.

As yet another embodiment, a method includes, while a patient is indirect contact with a fabric surface having a plurality of electrodesintegrated therein: receiving signals from the plurality of electrodes;selecting at least a first electrode of the plurality of electrodes as ameasurement electrode and a second electrode of the plurality ofelectrodes as a driven electrode based on the received signals;receiving and processing signals from at least the first electrode todetermine and output an electrocardiogram signal of the patient withreduced noise; and dynamically switching which electrode of theplurality of electrodes is selected as the driven electrode in responseto a change in which electrodes of the plurality of electrodes are indirect contact with the patient. In a first example of the method, thedynamically switching includes receiving a signal that the secondelectrode is no longer in direct contact with the patient and selectinga different, third electrode out of the plurality of electrodes as thedriven electrode and switching to delivering a driven common mode outputsignal to the patient from the first electrode to the third electrodewhile continuing to determine and output the electrocardiogram signal.In a second example of the method, which optionally includes the firstexample, selecting at least the first electrode of the plurality ofelectrodes as a measurement electrode includes receiving signals fromthe plurality of electrodes, determining which signals indicate acorresponding electrode of the plurality of electrodes is in directcontact with the patient, and processing signals of each correspondingelectrode indicated as being in direct contact with the patient todetermine the electrocardiogram signal and further comprising displayingone or more of the determined electrocardiogram signal and a heart ratedetermined from the electrocardiogram signal via a display device.

As used herein, an element or step recited in the singular and proceededwith the word “a” or “an” should be understood as not excluding pluralof said elements or steps, unless such exclusion is explicitly stated.Furthermore, references to “one embodiment” of the present invention arenot intended to be interpreted as excluding the existence of additionalembodiments that also incorporate the recited features. Moreover, unlessexplicitly stated to the contrary, embodiments “comprising,”“including,” or “having” an element or a plurality of elements having aparticular property may include additional such elements not having thatproperty. The terms “including” and “in which” are used as theplain-language equivalents of the respective terms “comprising” and“wherein.” Moreover, the terms “first,” “second,” and “third,” etc. areused merely as labels, and are not intended to impose numericalrequirements or a particular positional order on their objects.

This written description uses examples to disclose the invention,including the best mode, and also to enable a person of ordinary skillin the relevant art to practice the invention, including making andusing any devices or systems and performing any incorporated methods.The patentable scope of the invention is defined by the claims, and mayinclude other examples that occur to those of ordinary skill in the art.Such other examples are intended to be within the scope of the claims ifthey have structural elements that do not differ from the literallanguage of the claims, or if they include equivalent structuralelements with insubstantial differences from the literal languages ofthe claims.

1. A fabric cover for an infant incubator or warmer, comprising: aplurality of electrodes spaced apart from one another within ameasurement area of a surface of the fabric cover adapted to have directcontact with a patient, the plurality of electrodes including a topmostelectrode extending across an entire width of the measurement area, abottommost electrode extending across the entire width of themeasurement area, and a set of electrodes arranged between the topmostelectrode and bottommost electrode, in a direction perpendicular to thewidth, within the measurement area.
 2. The fabric cover of claim 1,wherein each electrode of the set of electrodes extends across amajority of the entire width of the measurement area.
 3. The fabriccover of claim 1, wherein each electrode of the set of electrodes isarranged directly adjacent to two other electrodes of the set ofelectrodes and one of the topmost and bottommost electrodes.
 4. Thefabric cover of claim 1, wherein the topmost electrode and thebottommost electrode are dedicated, driven electrodes and wherein eachelectrode of the set of electrodes is a measurement electrode.
 5. Thefabric cover of claim 1, wherein each electrode of the plurality ofelectrodes and the fabric cover are porous.
 6. The fabric cover of claim1, further comprising at least one electrical connector and a pluralityof electrical leads, each electrical lead of the plurality of electricalleads being insulated from the plurality of electrodes via a dielectriclayer and extending between a respective electrode and the at least oneelectrical connector.
 7. The fabric cover of claim 6, wherein the atleast one electrical connector is wirelessly connected to a signalprocessing circuit via a wireless electrical connection.
 8. The fabriccover of claim 6, further comprising an integrated electronic layerelectrically coupled to the at least one electrical connector andadapted to perform measurements on electrical signals received from theplurality of sensors.
 9. The fabric cover of claim 8, wherein theintegrated electronic layer includes a dynamic switching circuitincluding an input switch matrix and output switch matrix adapted toswitch which electrode of the plurality of electrodes is driven tooutput a driven common mode output signal and which signals receivedfrom the plurality of electrodes are used to determine anelectrocardiogram signal of the patient.
 10. The fabric cover of claim1, wherein the plurality of electrodes receive electrical power via abattery incorporated into the fabric cover.
 11. The fabric cover ofclaim 1, wherein each electrode of the plurality of electrodes is anelectrode pad including silver deposited electrode layers and whereineach electrode and a corresponding electrical connection between theelectrode and an electrical connector or measurement electronics isconductive while a remainder of the fabric cover is non-conductive. 12.A system for measuring bio-potentials of a patient, comprising: aplurality of electrodes spaced apart from one another along a surfaceadapted to be placed in direct contact with the patient; and anelectronic processor in electronic communication with each of theplurality of electrodes and adapted to: obtain signals output from atleast two measurement electrodes of the plurality of electrodes that arein direct contact with the patient and dynamically switch whichelectrode of the plurality of electrodes is selected as a drivenelectrode while at least a portion of the surface is in contact with thepatient.
 13. The system of claim 12, wherein the plurality of electrodesincludes a first set of dedicated, driven electrodes adapted to onlyoutput a driven common mode output signal and second set of measurementelectrodes adapted to measure bio-potentials of the patient, where thedriven electrode is selected from the first set of dedicated, drivenelectrodes and the two measurement electrodes are selected from thesecond set of measurement electrodes.
 14. The system of claim 13,wherein the first set of dedicated, driven electrodes includes at leasttwo electrodes, wherein there are a greater number of electrodes in thesecond set of measurement electrodes than the first set of dedicated,driven electrodes, and wherein the plurality of electrodes are spacedapart from one another via a gap, that gap including material thatinsulates adjacent electrodes from one another.
 15. The system of claim12, wherein the electronic processor is further adapted to: determinewhich electrodes of the plurality of electrodes are in direct contactwith the patient based on individual skin impedance measurementsreceived from each electrode of the plurality of electrodes and selectthe driven electrode to be an electrode having an individual skinimpedance measurement at a threshold level.
 16. The system of claim 15,wherein the electronic processor is further adapted to determine anelectrocardiogram signal of the patient from signals output by the atleast two measurement electrodes, the at least two measurementelectrodes determined to be in direct contact with the patient, whereinthe electrodes having signals used for determining the electrocardiogramsignal do not include the selected driven electrode.
 17. The system ofclaim 16, wherein the electronic processor is further adapted todetermine a heart rate of the patient from the determinedelectrocardiogram signal and display, via a display device, one or moreof the determined heart rate and electrocardiogram signal.
 18. A method,comprising: while a patient is in direct contact with a fabric surfacehaving a plurality of electrodes integrated therein: receiving signalsfrom the plurality of electrodes; selecting at least a first electrodeof the plurality of electrodes as a measurement electrode and a secondelectrode of the plurality of electrodes as a driven electrode based onthe received signals; receiving and processing signals from at least thefirst electrode to determine and output an electrocardiogram signal ofthe patient with reduced noise; and dynamically switching whichelectrode of the plurality of electrodes is selected as the drivenelectrode in response to a change in which electrodes of the pluralityof electrodes are in direct contact with the patient.
 19. The method ofclaim 18, wherein the dynamically switching includes receiving a signalthat the second electrode is no longer in direct contact with thepatient and selecting a different, third electrode out of the pluralityof electrodes as the driven electrode and switching to delivering adriven common mode output signal to the patient from the first electrodeto the third electrode while continuing to determine and output theelectrocardiogram signal.
 20. The method of claim 19, wherein selectingat least the first electrode of the plurality of electrodes as ameasurement electrode includes receiving signals from the plurality ofelectrodes, determining which signals indicate a corresponding electrodeof the plurality of electrodes is in direct contact with the patient,and processing signals of each corresponding electrode indicated asbeing in direct contact with the patient to determine theelectrocardiogram signal and further comprising displaying one or moreof the determined electrocardiogram signal and a heart rate determinedfrom the electrocardiogram signal via a display device.